1. Field of the Invention
The present invention relates generally to a hot airflow generation device, and in particular to a hot airflow generation device that allows for regulation of flow rate and direction adjustment of air flowing toward an article around which a heat-shrinkage film wraps.
2. The Related Art
Heat-shrinking plastic films have been widely used to wrap and pack consumer products, such as foods, books, video/audio compact disks for protecting the products from contamination and damage. A packaging machine is required to warp the package film around the product and supply hot airflow to heat the plastic film in order to have the film shrunk and thus securely wrapping around an article to be packaged.
Conventionally, hot airflow is supplied from the top side of a hot airflow generation device. The hot air is guided downward to an article to be packaged by the heat-shrinkage film. The airflow then randomly bounces away from the article. Thus, uniformly and quickly heating the film can rarely be realized. In addition, articles to be packaged may have totally different shapes and dimensions. The one-way hot airflow generated and provided by the conventional hot airflow generation device is thus not capable to achieve high quality packaging.
Thus, it is desired to have a device for generating hot airflow that is applied to heat-shrinkage film in order to overcome the above problems.
An object of the present invention is to provide a hot airflow generation device comprising a casing inside which hot air is caused to continuously circulate for inducing uniform heating on an article to be packaged.
Another object of the present invention is to provide a hot airflow generation device comprising air flow guides for controlling direction and flow rate of hot air flowing toward an article to be packaged to provide excellent quality of packaging.
To achieve the above objects, in accordance with the present invention, there is provided a hot airflow generation device for supplying hot airflows toward a heat-shrinkage film wrapping around an article to heat and shrink the film, forming a package over the article. The hot airflow generation device comprises a casing defining a channel through which the article wrapped by the heat-shrinkage film is conveyed. A hood is arranged inside the casing and forms air passages with the casing. Each air passage forms an exit opening. The hood is comprised of walls forming an air intake port in communication with the air passages. An air fan is mounted to the hood for drawing air into the air intake port and driving the air into the air passages. Electric heaters are arranged inside the air passages for heating air flowing therethrough. Air that is drawn into the air intake port and driven through the air passages is heated by the heaters and becomes hot airflow that flow toward the article through the exit openings. The air bounces from the article and is drawn into the air intake port and the air passages again for circulation and being heated again. An airflow guide board is rotatably mounted in each air passage for controlling air flow rate and direction through the associated exit opening.